Liquid level switch



` vMay 22, 1945- J. R. MUMA ET AL 2,376,377

LIQUID LEVEL sw'rcH Filed July 19, 1943 2 sheets-Sheet 1 will'. f f 23SO 24 lO 29 20H 30 19 VENTORS UMA' f M wlLsoN, JR.

BK @ya JR. wam' TT'oRN Y May 22, 1945. J. R. MUMA ET AL 376,377

A' LIQUID LEVEL SWITCH Filed July 19, 1231-15A 2 Sheets-Sheet 2 FloINVENTORS'. J. R. MUMA E. J. WILSON, JR.

of the switch.

Patented May 22, 1945 LIQUID Lavar. swrrcn John R. Muma, Northport, andElwood il. Wilson, Jr., and Robert Haskins, Jr., Garden City, N. Y.,assignors to Sperry Gyroscope Company',l Inc., a corporation of New YorkApplication July 19, 1943, Serial No. 495,298

v 9 Claims. (Cl. 20o-152) receptacle. Bosses l2, Il. Il and I are formedThis invention relates to an electrical switch of the liquid level typein which the relative positionof the bubble therein Awith respect to anumber of conducting terminals determines the selectivity The primaryfeature of the invention resides in the provision of a liquid enclosingreceptacle having bosses therein which guide the bubble in" its movementrelative to the terminals.

Other features and structural details of the invention will be apparentfromthe following.

description when read in connection with the accompanying drawings,wherein. l Fig. 1 is a top plan View of the receptacle forming the baseof a switch constructed in accordance' with the present invention.'

Fig. 2 is a vertical section view of an assembled switch having a baseas shown in Fig. 1.

Fig. 3 is a bottom plan view of the cover member of the receptacle. I,

Fig. 4 is a view similar to Fig. l, showing a modified form of base.

Fig. 5 is a section view taken inline 57-4, in Fig. 4.

Fig. 6 is a top plan viewof a switch constructed in accordance with theinvention.

Fig. 'l'is a view similar to Fig. 2 showing a further modification ofthe invention.

Fig. 8 is a bottom plan view of the cover or closure member utilizedwith the form oi' switch shown in Fig. 1, and

Figs. 9 andi() are views similar to Fig.' 8 showing separate modifiedconstructions of the cover of the switch.

With reference particularly to Figs. 1,-2, 3 and 6, a switch constructedin accordance with the invention is shown to include a closed receptacleI0 which is generally cup-shaped and contains a current conducting fluidIl therein. The receptacle lis formed to include a number ofsymmetrically arranged internal bosses as indicated at l2, Il, I4 andl5. Theside walls of the adjacent bosses define a number of channels I6,I1, It and I9 that serve as guide passage ways for the bubble alsocontained within the closed receptacle. In the present instance, thereceptacle which may also be considered to include a cover or closurepart 2l is constructed of insulating material. The bottom wall of thereceptacle is plated with a curu rent conducting material as indicatedat I9" and a lead connected thereto passes through the insulating bodyof the receptacle and provides a circuit completing means for leadingelectrical energy from a suitable Asource to the liquid in the in thebody ot the receptacle, in this instance, the

same being, symmetrically arranged around the. inside periphery thereof.

The closure or cover portion of the receptacle l0 may be fitted thereinby means of clamping ring and llanged parts respectively indicated at 22and '23 that are brought into engagement. A resilient washerA 2,4 maybeemployed between the connected parts to prevent any leakage of theiiuid Il.

The cover 2| is also constructed of insulating f material and as showninvdetail in Fig. 3 is cylin drically shaped to nt over the top of thecupshaped base of the receptacle. The cover part includes a number ofelectrical terminals 25, 2B, 21 and 2l which are equldistantly spacedfrom the center of the part as weil as with respect to one another. Arecess is provided lor each of the inwardly disposed ends of theterminals on the underside ol the cover, the exposed faces of theterminals being substantially flush with the inside wall of the cover orthe surface over which the bubble moves. The central portion of theinside top wall of the closed receptacle is formed slightly concave asindicated at 2l. The cover 2l projects sufilclently vfar into the baseportion of the receptacle as to leave'little clearance between the rtopof the bosses and theinside wall of the cover. The inwardly disposedends of the terminals are situated in the respective channels so thatwhen the receptacle is inclined from a normal position, the bubble IIIwithin the receptacle moves from its central position to one in which,guided by the channels, it covers one or more of the inwardly disposedfaces of the terminals to thereby open the circuit through this portionof the switch. In use, the improved switch may be secured to the rotorcase of a gyro vertical instrument in the manner particularly shownanddescribed in the copending application of O. E. Esval and J. R. Muma,for Tilt correcting devices, Serial No. 428,040, iiled January 24, 1942.

With reference to Figs. 4 and 5, a modified form of liquid containingreceptacle is illustrated. In this instance, the base of the receptaclel0' is a metal cup constructed of current conducting ma terial whosewalls are indented to form the bosses I2', I3', it' and l5 therein. Lead20' is directly connected to the conducting receptacle. A cover part ofthe character shown in Fig. 2 may be employed with this type of switch.

A further modication of the invention is shown in Figs. 'l and v8, inwhich the bosses are formed. on. tlie cover ill ci? the ctvitcli cettenoted et it", i3", it end lo". lille lcoeeec on the cover projectinwerdly into o. hollow ouin shaped receptacle loose itl which niet" leenie-tde or current conducting motorini. `@Sewer lll ls constructed otineuletiiief moterlel end like the closure lll includes on electrloelterminal mount ed therein for eeen of the -cliennele il', lli', it', endlill termed therein. by' the bosses. The ter initials are indicatedrespectively et 25', lili', tl' end itl.

lin the type ci tierces illustroted in. l'ies. and li, the tin sucurved, tlio il, c. the come ie silently inline chennele tlutt etre olieulistentiolly cons` nl, width throughout the length thereof. Shown .in9, the tip sur foce cl' the respective bosses muy be etrelellt esinflected further form. of loose is shown l0, in which. the channelsdeilned thereby nitriet? in widtll. the come epproecli the rpe rinlieryolf the cover oi the recentocle. The curved bosses employed in thisconnection ore indicated ll'", il", ll'", end. 85"'.

inou? changes could be inode in the oliove construction und montopnerently widely dlilerm ent entendimiento of this invention could loemode Without dejo in; from the thereof, it intended tltet niet-tercontained .in tile ebow/e dement-lon. or eher i io. the eccompenylng die Yell loe interpreted ec illuetretlve cud no r. limiting "if 1ct lecloimedis:

n electricel :switch :formed of u clos-ed re le lievlne en unbrokensubstantielle incide upper well. current conducting tluid e,nonmcnrlucti. electing; liulotule filling cold recente cle, seidliulclile :moi/loe; alone seid upper lli. tilt ci Seid recejotocle fromnorruel munter ci' synoo?. *rior-.illy erreneed ,ctive guide themovements olcctricel terminol mounted tele extending to puel iutli. with.told inside upper "witch, nomine' e, togo geert, id ton leert ond'ieretvitlo tilteble olor' d ton includes;

i nonwcozziduct entecle donnine' number of i iiuiolole, iilline; seid.e7

eletecle, .seid bubble moving clone the inside .voll ci sold ton portwith tilt oi seid recept-cele from e. normal position, e. number ooyminetricelly arranged bosses in said receptecle dennirlg en equal.number of channels therein ettective to guide the movements of thebubble, end en electrical terminal leading to each of the channels inseid receptacle, seid terminals heine mounted on seid top port endextending to e position substentielly flush with the inside wallthereof.

3. .el switch es claimed in claim 2, in which said bottom port leconstructed of insulating material llevlne o current conducting platingapplied to the interior 'woll thereof.

Il. A switch es claimed in cleim 2, in which eeid bottom port leconstructed of conducting meteM rial end the wolle thereof are indentedto form the bosses therein.

A switch es cleimed in claim 2,111 which seid top port is constructed toinclude the bosses thereon.

6. .lin electrical switch having o. cylindrical cover with en innerWell, unbroken and substantiolly not, e Cupelleped loose fitting on theperipliery of sold cover ond forming therewith e. tiltoble closedreceptacle, o. current conducting :duid end e. nowconducting floatingbubble filling scid. receptecle, seid bubble moving,r along the innerwell of seid cover from the center toward the periphery thereof withtilt of the receptacle from e, normol position, e number o1 symmetryerronfged bosses in said receptacle defining an equel. ntunber ofchannels therein effective to guide the movements of the bubble, endelectrical terminals in seid cover, each of which extends to one olfseid channels ond is substantially flush with the inner well. of thecover.

7. A switch es claimed in cleim 6, in which seid lcoeees ere constructedes e. port of the co" .Il switch ee cla-timed in clem 6, in which seiddenne etienne-le thet morrow in width as time seme approach theperiphery of the receptocle.

il. .ci svrltcli es elomedin claim 6, in which the control portion ofthe inner Well of the cover is slightly concetto.

